Need advise with molds please

[kevin926]

Hello

I’m trying to use a simple dump mold for my training remote but I made more of a dump rather than parts

I will post pics when I get home but I was hoping I can have some advise or some do and do nots

photos or choice brands of mold kits would be huge

thanks in advance
Kevin

 

[Jkirkon]

Some pics of what you’re trying to do would be helpful.
Here is a pretty decent tutorial on making simple 2 part molds, maybe it will be helpful:

Two Part Molds

Two Part Molds: I try as hard as I can to keep all my silicone mold making in the form of flexible block molds. Frankly, they take less time. But once in awhile, you come across a model that you HAVE to reproduce and it demands a two part mold.

www.instructables.com

 

[kevin926]

 

[kevin926]

These are for a training remote. I used hot glue to hold in place, poured the mold and let cure for 24 hours.

Poured my resin and this was my end result. Not very good looking molds or castings

 

[Jkirkon]

What materials are you using, for mold material and casting resin?

I use Smooth On OOMOO for rubber, and Smooth Cast 310 for resin.
I degas the rubber (although it’s not really needed with OOMOO) in a vacuum chamber, and pressure cast the parts.

Use styrene to make a mold box, or make one from LEGOs. I use CA glue to tack my original parts to a piece of styrene, then build a mold box around them.

Take a look at the link I posted earlier.

 

[acesh007]

Id also suggest using smooth-on products. I usually use moldstar16 or 20T and smooth cast 300 for resin.

 

[newmagrathea]

I'm assuming you don't have a degassing chamber (me either). I'm not sure if this tip is 100% legit but it made sense to me. Pour a very thin amount (think dry spaghetti noodle, or less if you can), raising the resin as you poor, the idea is that any large bubbles will be released as it's poured. I've done this with success, at lease I didn't have bubbles on the detail side of the cast, there were plenty on the back but who cares about that. Also I think the cupola mold would need to be a two parts for the casts to look/work correctly.

 

[kevin926]

Using this brand . Resin is the same

 

[kevin926]

I'm assuming you don't have a degassing chamber (me either). I'm not sure if this tip is 100% legit but it made sense to me. Pour a very thin amount (think dry spaghetti noodle, or less if you can), raising the resin as you poor, the idea is that any large bubbles will be released as it's poured. I've done this with success, at lease I didn't have bubbles on the detail side of the cast, there were plenty on the back but who cares about that. Also I think the cupola mold would need to be a two parts for the casts to look/work correctly.

N

I'm assuming you don't have a degassing chamber (me either). I'm not sure if this tip is 100% legit but it made sense to me. Pour a very thin amount (think dry spaghetti noodle, or less if you can), raising the resin as you poor, the idea is that any large bubbles will be released as it's poured. I've done this with success, at lease I didn't have bubbles on the detail side of the cast, there were plenty on the back but who cares about that. Also I think the cupola mold would need to be a two parts for the casts to look/work correctly.

No chamber. . I am going to remake my mold. I also bought some two sided tape .I can't help but think some of the hot glue took away definition

 

[Jkirkon]

Tack glue it using a tiny drop of super glue. get rid of the cardboard mold box, use styrene.

I swear by smooth on products.

 

[TazMan2000]

White glue works to tack down the parts as well. This way you can reuse the part.

TazMan2000

 

[clonesix]

Hi Kevin,
Please allow me to offer a Nickle's worth of free advice:

1. Throw out that rubber and resin that you got at the craft shop. It is beneath what you are trying to do here.
2. Smooth-On.com has rubber and resin for what you want to do. they also have videos.
3. Lose the cardboard. start with a solid surface, styrene, acrylic, glass... I like styrene because it cuts with a score and a snap.
4. Hot glue is fine for attaching parts to the surface, but be sure the pieces are mounted firmly.
5. I also see in the top box that there are pieces with hollow centers. This must be filled with clay to avoid locking the piece in.

 

[kevin926]

I see multiple choices on the smooth on site.. what do you recommend

 

[tsenecal]

I use Mold-Max 30 for my moulds, and smooth-cast 321 for my resin.

I see multiple choices on the smooth on site.. what do you recommend

 

[swgeek]

I use foam core for my mold boxes. It's easy to cut, It glues well and if you glue original parts down to it with ca, you only have to sand off a little bit of paper.

 

[Studio Kitbash]

Kevin926,

Everything I needed to know about molding and casting I learned from Dave Goldberg's Y-Wing tutorial on the subject, available here in the Y-Wing threads. Basically, you need to think about it as "precision surgery" rather than "rough carpentry" -- it takes some time to develop the skills, some practice and patience, and some understanding (through trial and error) of how the many variables work together. But it is utterly satisfying once you get it.

Cheers,

SK

 

[OlivierC]

Dave's tutorial is indeed a very good start.

I have also learned a lot watching this series of videos, I recommend it to anyone who wants to get into mold making :

Molding & Casting 101

A beginner's course in making silicone molds and casting prop and costume parts from urethane plastic resin.

www.youtube.com

SmoothOn products are expensive, but they worked very well for me. For silicons, their two main products are moldMax and MoldStar. first one is Tin based and the other Platinium based. Platinium will last longer but is more sensitive of other chemicals. So if you use certain types of clays or paint on the part you want to cast it can mess up the curing. but if it's just doing plastic parts, you should be fine. I think mold star is a bit easier to use too because the mixing ratio between compound A and B is 1:1.

For the resin I generally use smoothcast 300-305 or smoothcast 65D for rotocasting, but I don't think you'll need this for your project

Edit : pressure pot and degazing chamber are pretty big investments and you can already get very decent results without them. if it's just a one off thing, you can skip them. I don't have a pressure pot personally.

 

[scotthothpatrol]

For the mold box I do the same as SWGEEK making it out of foam core board and gluing together with hot glue. To secure the parts to the mold box I use crazy glue or double sided tape. For the mold material I use Mold max 30 and smooth cast 300 for resin. If you want to give resin a different color you can mix in a little oil paint. and since silicone can get expensive I recycle old molds by cutting them up into small cubes and adding them to the pour. For a new mold give it a going over with talc powder or corn starch.

 

[kevin926]

Thanks everyone. I ordered my mold and resin . I did buy the plastic form board I saw from the first video posted above. I have lots of styrene in my shop. I'm making a full size styrene R2. Never thought about using it. .

I will begin making a mold stock and wait for my order to arrive.

What are you using to release.. can I use pam cooking oils.

 

[Studio Kitbash]

I've never used any mold release agents, and don't recommend them, though do often use a light dusting of baby powder before pouring resin into a mold.